[Android WebView] Turn off compatibility quirks in tests

All tests now run in "quirkless" mode, except for the tests that
explicitly test quirks behavior. Since almost all of them are in AwViewportTest
suite, I have moved the remaining one from AwSettingsTest into it, and renamed
AwViewportTest to AwLegacyQuirksTest.

BUG=278106
R=benm@chromium.org

Review URL: https://codereview.chromium.org/159983010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251681 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251681